1. Field of the Invention
The present invention relates to a device for adding fluctuation (wavering, swing or sway) to an electronic sound apparatus and to a method thereof. More particularly, the invention relates to a device for imparting fluctuation to a tone that is generated and to a method thereof.
2. Prior Art
Examples of such a device for adding fluctuation has been disclosed in Japanese Patent Application No. 346063/1992 entitled "Device for generating fluctuation waves in an electronic sound apparatus" and Japanese Patent Application No. 043933/1993 entitled "Sound fluctuation system in an electronic sound apparatus" filed by the present applicant. In the devices disclosed in this application, fluctuation waveforms are added to the pitch and amplitude of sound that is generated, so that the pitch and amplitude undergo a fine change.
The fluctuation changes in various ways and in various modes. A tone never changes monotonously, but changes in a variety of ways depending upon the frequency components and upon the time components.